Agilent Technologies 4294A, Руководство по эксплуатации

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108 Chapter 5
Setting Measurement Conditions
Setting and Applying dc Bias
• Enter the desired value with the numeric keys (
[0]
to
[9]
,
[.]
, and
[-]
) and then press the
unit key (
[G/n]
,
[M/ m ]
,
[k/m]
, or
[ ´ 1]
).
• Turn the rotary knob (
m m m m
) until the desired value is set.
• Press the step keys ([
­
][
¯
]) to set the desired value.
3. Setting limits for dc voltage
When constant voltage or current is selected for the dc bias mode, follow the steps below to
set limit values for the voltage (upper and lower limits) in order to protect the DUT being
measured.
Step 1. Press the
MAX LIMIT VOLTAGE
key. This will display the current setting for the upper
limit of dc voltage for the segment in the parameter settings located in the upper left area of
the screen.
Step 2. Use the keys or rotary knob of the ENTRY block in one of the following ways to specify a
value for the upper limit of dc voltage.
• Enter the desired value with the numeric keys (
[0]
to
[9]
,
[.]
, and
[-]
) and then press the
unit key (
[G/n]
,
[M/ m ]
,
[k/m]
, or
[ ´ 1]
).
• Turn the rotary knob (
m m m m
) until the desired value is set.
• Press the step keys ([
­
][
¯
]) to set the desired value.
Step 3. Press the
MIN LIMIT VOLTAGE
key. This will display the current setting for the lower limit
of dc voltage for the segment in the parameter settings located in the upper left area of the
screen.
Step 4. Use the keys or rotary knob of the ENTRY block in one of the following ways to specify a
value for the lower limit of dc voltage.
• Enter the desired value with the numeric keys (
[0]
to
[9]
,
[.]
, and
[-]
) and then press the
unit key (
[G/n]
,
[M/ m ]
,
[k/m]
, or
[ ´ 1]
).
• Turn the rotary knob (
m m m m
) until the desired value is set.
• Press the step keys ([
­
][
¯
]) to set the desired value.
NOTE
When the dc bias applied to DUT exceeds the upper or lower voltage limit specified in the
above procedure, the error message “dcBIAS CONSTANT OPERATION FAILED” (error
number: 138) will be displayed in the instrument message area in the upper left part of the
screen.
The dc voltage limit values specified by the
MAX LIMIT VOLTAGE
or
MIN LIMIT VOLTAGE
key take effect when the dc bias mode is constant voltage or current.
The setting for these values is disabled when the dc bias mode is set to non-constant
voltage or current mode.
4. Setting dc bias range to 1 mA
Set the dc bias range before turning the dc bias ON. The dc bias range is set to optimize the
dc current given to the impedance measurement circuit. This setting affects the accuracy of
impedance measurement regardless of which dc bias mode is selected or whether dc bias is
turned ON or OFF. Normally, maximum accuracy can be obtained by setting the dc bias